Question: What is the grinder model with the lowest sound power level whose subclass of is grinding machine?
Paraphrase: In the subclass of grinding machine, which grinder model has the quietest power level?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q23811263 . ?ent wdt:P2797 ?obj . ?ent wdt:P279 wd:Q245761} ORDER BY ASC(?obj)LIMIT 5 
Answer: Ryobi AG451, Ryobi AG401, Hitachi G12SE2, Hitachi G12SR2, Makita 9557PB